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    #1

    Dumb question from a noob

    I have a 32" viewsonic (n3251w) i'm working on and the backlight will not work. The power board had insufficient output voltages on the HV side and i couldn't ever pick out the right component. I found a new board at a good price and now the voltages are correct but still no backlight. My question is does the mainboard send a signal to power the inverter or should it be ok if as long as the PS output is ok? I'm getting a little frustrated with it at this point. Inverter doesn't look burned but haven't tested anything except the fuse.
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    #2
    Re: Dumb question from a noob

    Originally posted by rmoody View Post
    I have a 32" viewsonic (n3251w) i'm working on and the backlight will not work. The power board had insufficient output voltages on the HV side and i couldn't ever pick out the right component. I found a new board at a good price and now the voltages are correct but still no backlight. My question is does the mainboard send a signal to power the inverter or should it be ok if as long as the PS output is ok? I'm getting a little frustrated with it at this point. Inverter doesn't look burned but haven't tested anything except the fuse.
    The inverter is USUALLY controlled from the main board.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

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      #3
      Re: Dumb question from a noob

      Ok after stripping it down and looking at the inverter i put it all back together and found that the backlight actually comes on for maybe a second and shows the picture then black right back out. I'm guessing this is a problem with my main board.

      Comment

        #4
        Re: Dumb question from a noob

        More likely an inverter problem.

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          #5
          Re: Dumb question from a noob

          Originally posted by rmoody View Post
          Ok after stripping it down and looking at the inverter i put it all back together and found that the backlight actually comes on for maybe a second and shows the picture then black right back out. I'm guessing this is a problem with my main board.
          Bad lamp.

          Comment

            #6
            Re: Dumb question from a noob

            Sounds like two seconds to black. I learned the hard way to do a little testing before jumping to conclusions. A very simple test is to check the voltage on the inverter control pin. It is often labeled On/Off, or Inv_On. If it goes high (typically 3.3 volts) while the backlights are on, then goes low, the main board is shutting down the inverter. If it remains high while the backlights go off, it's an inverter or CCFL problem.

            Another even simpler test is to hook up a video game, DVD player, or even tune to an over the air channel. Select that input by pressing the appropriate button. (On some TVs pressing the Input button advances to the next input). If you can hear the audio while the backlights are off, it's an inverter or CCFL problem.

            PlainBill
            For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

            Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

            Comment

              #7
              Re: Dumb question from a noob

              Originally posted by PlainBill View Post
              Sounds like two seconds to black. I learned the hard way to do a little testing before jumping to conclusions. A very simple test is to check the voltage on the inverter control pin. It is often labeled On/Off, or Inv_On. If it goes high (typically 3.3 volts) while the backlights are on, then goes low, the main board is shutting down the inverter. If it remains high while the backlights go off, it's an inverter or CCFL problem.

              Another even simpler test is to hook up a video game, DVD player, or even tune to an over the air channel. Select that input by pressing the appropriate button. (On some TVs pressing the Input button advances to the next input). If you can hear the audio while the backlights are off, it's an inverter or CCFL problem.

              PlainBill
              Well I was fortunate enough to find a Main Board and an extra set of speakers on ebay for $24 shipped to my door. When it comes in I'll let you know the outcome. I would try the inverter but man that thing is buried deep in this tv. The power board and Main board have to come off followed by a large metal cover with about 40 screws just to get to it.

              Comment

                #8
                Re: Dumb question from a noob

                Must be the inverter or the CCFL Problem. Some times a bad lamp could cause the inverter to shut down.

                Comment

                  #9
                  Re: Dumb question from a noob

                  Originally posted by Sir farts alot View Post
                  Must be the inverter or the CCFL Problem. Some times a bad lamp could cause the inverter to shut down.
                  IDK, but at this point I hope it's the main board.

                  Comment

                    #10
                    Re: Dumb question from a noob

                    FIXED, turned out it was the inverter. Got one at a decent price so i went ahead and replaced it. Now i have a good power board i gotta sell

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